Electrically charged fences are designed to impart an electrical shock to an animal by establishing an electrical circuit between ground and a source of electrical potential through an animal. These systems commonly utilize a single wire, a double wire or two separate wires.
The single wire system includes an uninsulated wire connected to a fence charger wherein an animal upon touching the wire causes the current to flow from the wire through the animal to the ground. If the ground or soil condition is frozen or dry there is a sharp increase in the electrical resistance of the current path through ground so as to reduce the current flow and shock sometimes to such a low value that the electrically charged fence becomes ineffective.
The double wire system has longitudinally spaced contact plates with alternate plates connected to one wire and the other plates connected to the other wire. The one wire is connected to the fence charger and the other wire is connected to ground. During normal, dry or cold weather conditions when adjacent contacts are bridged by an animal the current shocks the animal. However, during some particular weather conditions there is a leakage of the shocking current on the insulated sections between adjacent contacts, thus making the cable ineffective for livestock control.
The two wire system overcomes the problem of dry or frozen conditions by utilizing a ground wire above or below the charged wire; however, this system is not always effective where controlled feeding of cattle is desired.